In various photographic studies, knowledge of the positional coordinates of the lens node of a camera is of particular interest. By way of example, in a recently developed method for three-dimensional object reproduction, disclosed in commonly-assigned copending application Ser. No. 412,162, steps are disclosed for the generation, from examination of a specially derived photograph, of electrical signals selectively identifying that light ray or optical path, in a bundle of rays or paths extending from a camera lens to an object, which is in viewing relation to a given object surface boundary point of interest. Where the positional coordinates of the location of the camera lens node are known, such signals are useful in reconstructing the point of interest in exacting spatial relation to other points cooperatively defining the entire object surface boundary.
In the event that environmental disturbances, such as vibration, or intended camera movement, occur in the practice of the particularly referenced method, and where exacting object reproduction is desired, it is necessary to redetermine the initial, tediously determined positional coordinates of the location of the camera lens node. Given such conditions in the referenced and other methods, need exists for apparatus and methods facilitating ready determination and redetermination of camera lens node position.